1. Field of the Invention
The present invention relates to a refrigerant compressor for use in refrigerators, air conditioners, heat pumps and so forth.
2. Description of the Prior Art
Hitherto, there have been proposed various types of lubrication systems for refrigerant compressors. For instance, in the refrigerant compressors having a vertical crank shaft, the lubricating oil is supplied by means of a viscosity pump or a pump which sucks and delivers the oil by making use of centrifugal force. Similarly, in the refrigerant compressors having a horizontal crank shaft, the supply of the lubricating oil is made by a mechanical pump such as a gear pump or by the action of a splash ring. It is also known to use a bubble pump making use of the flowing velocity of the compressed gas or to make use of a pressure differential in supplying the lubricanting oil.
The gear pump can stably supply the lubricating oil at a sufficiently high pressure and at a large delivery rate, but the cost of the gear pump is generally high. The splash ring, which is less expensive, cannot provide a sufficiently high delivery rate. The bubble pump or the lubricating system making use of the pressure differential also involves some problems concerning the rate of delivery of the lubricating oil, although the cost thereof is moderate.